Question

Error Analysis - Describe the error in a sentence or two. Then, solve the problem

correctly.
13. If f(x)=2x-1, then find the x-value so that f(x) = 21.
A f(21) = 2(21)-1
B
f(21) = 42 - 1
C
f(21) = 41
The error was in line A, B, or C
The correct answer is [ans]

Answer 1

The error is in line A. f(x), not x, is equal to 21.

f(x) = 2x - 1 = 21

2x = 20, so x = 10.